Last modified: Monday, November 24, 2008 10:16 AM PST Ore. suit challenges plan to burn mustard agent PENDLETON  (AP) — An Oregon lawsuit challenging the destruction of mustard gas through incineration says regulators didn’t take a close enough look at two alternatives. The Umatilla Chemical Depot in Eastern Oregon is getting ready to incinerating mustard containers sometime next year. The containers, which weigh a ton each, contain mercury, a hazardous substance. On Oct. 31, the Government Accountability Project, a public advocacy group, sued the Oregon Environmental Quality Commission and the Department of Environmental Quality. It asks a judge to block a decision that incineration is the ‘‘best available technology’’ for destroying the large mustard containers. Stockpiles of Sarin and VX nerve agent have already been burned at the depot. The group filed the lawsuit in Multnomah County Court on behalf of the anti-incineration group GASP, the Oregon Wildlife Federation, Sierra Club and several residents of Umatilla and Morrow Counties. Richard Condit, senior counsel for the Government Accountability Project, said the state agency didn’t adequately review two other technologies, neutralization and a contained-explosion process. ‘‘It’s just been a flawed process because of the bias toward incineration,’’ Condit said. He said neutralization proved effective at Aberdeen, Md., where the Army used it on mustard agent. Aberdeen finished its munitions destruction in 2006 and then closed.